1. Field of the Invention
The invention is related generally to illumination systems, more particularly, to driving circuits for use in illumination systems.
2. Description of the Related Art
FIG. 1A is a schematic diagram of an illumination system. As shown in FIG. 1A, the illumination system 100 includes a driving circuit 110 and an illumination module 120. The driving circuit 110 includes n channels to drive the illumination units ED1˜EDn of the illumination module 120, and each of the illumination units ED1˜EDn is coupled to the power line Vp.
FIG. 1B is a diagram depicting the graph of the current on the power line versus time. As shown in FIG. 1B, the waveform Cv1 represents the current of the first channel, the waveform Cv2 represents the current of the second channel, the waveform Cv3 represents the current of the third channel, and the waveform Cvn represents the current of the n-th channel. The waveform Cvs represents the total current summing up all the current waveforms from the waveform Cv1 to the waveform Cvn, which is equivalent to the current of the power line Vp.
Note that since the n channels are simultaneously turned on at the beginning of each display cycle DP, the current of the power line Vp instantly surges from zero to a value being n times the current value of a single channel. This causes the noise to be over-concentrated at the beginning of the display cycle DP. Therefore, a driving circuit and a driving method are needed which can evenly distribute the current of the power line Vp through the display cycle DP.